U.S. patent number 4,892,324 [Application Number 07/234,517] was granted by the patent office on 1990-01-09 for fifth wheel mounting pad.
This patent grant is currently assigned to Amsted Industries Incorporated. Invention is credited to Terry L. Pitchford, Robert P. Radwill, Charles P. Spencer.
United States Patent |
4,892,324 |
Spencer , et al. |
January 9, 1990 |
Fifth wheel mounting pad
Abstract
An improved fifth wheel structure for over the road tractors
wherein a resilient elastomer pad placed between a fifth wheel
pocket surface and a bearing surface includes non-extrudable end
members to prevent extrusion of the pad from the pocket and wherein
the pocket surface and corresponding shoe surface may also be
undulated to better retain the elastomer pad.
Inventors: |
Spencer; Charles P. (Staunton,
IL), Pitchford; Terry L. (St. Louis, MO), Radwill; Robert
P. (Burr Ridge, IL) |
Assignee: |
Amsted Industries Incorporated
(Chicago, IL)
|
Family
ID: |
22881686 |
Appl.
No.: |
07/234,517 |
Filed: |
August 22, 1988 |
Current U.S.
Class: |
280/440;
267/292 |
Current CPC
Class: |
B62D
53/0885 (20130101) |
Current International
Class: |
B62D
53/00 (20060101); B62D 53/08 (20060101); B62D
053/08 () |
Field of
Search: |
;403/225,226,228
;280/439,440 ;267/153,292 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mitchell; David M.
Assistant Examiner: Mar; Michael
Attorney, Agent or Firm: Bouton; Charles E. Brosius; Edward
J.
Claims
What is claimed is:
1. An improved fifth wheel mounting wherein mounting brackets
attached to a tractor frame have arcuate bearing surfaces that are
received within pockets on the underside of the fifth wheel toward
arcuate pocket surfaces therein with an arcuate shoe placed between
said surfaces, said improvement comprising:
an inwardly directed ledge at each end of one of said arcuate
pocket surface and said arcuate shoe, said ledge reducing but not
closing an open space between said arcuate pocket surface and said
shoe;
a resilient elastomer pad interposed between said arcuate pocket
surface and said shoe said pad having an end proximate each said
inwardly directly ledge;
and a non-extrudable end member located at each end of said pad and
between said arcuate bearing surface and said arcuate shoe and
inwardly of each ledge, said end member extending substantially the
width of said elastomer pad whereby to completely block extrusion
of said pad from the inside between said arcuate pocket surface and
shoe when a load is placed on said fifth wheel causing said pad to
be compressed while still allowing for relative movement between
said arcuate pocket surface and said shoe to provide a cushioning
effect.
2. The improved fifth wheel mounting of claim 1 wherein said
arcuate pocket surfaces and shoe are sufficiently curved in cross
section that the ends thereof slip with respect to one another and
do not substantially close upon said pad being compressed.
3. The improved wheel mounting of claim 1 wherein the said ledges
are formed on said arcuate pocket surface whereby said open space
between said arcuate pocket surface and said shoe increases when a
load is placed on said fifth wheel.
4. The improved fifth wheel mounting of claim 1 wherein said
non-extrudable end member is a bar butted against an end of said
pad.
5. The improved fifth wheel mounting of claim 1 wherein said
non-extrudable end member is a bar imbedded in the end of said
pad.
6. The improved fifth wheel mounting of claim 1 wherein said
non-extrudable end member is a clip secured to the end of said
pad.
7. In a movable connection between an arcuate bracket bearing
surface and a load bearing pocket arcuate surface wherein an
elastomer pad is interposed between the pocket surface and the
bracket bearing surface, the improvement comprising:
an arcuate shoe positioned between said bracket bearing surface and
said pocket arcuate surface;
an inwardly directed ledge at each end of one of said arcuate
pocket surface and said arcuate shoe, said ledge reducing but not
closing an open space between said arcuate pocket surface and said
shoe;
a resilient elastomer pad interposed between said arcuate pocket
surface and said shoe, said pad having an end proximate each said
inwardly directed ledge;
and a non-extrudable end member located at each end of said pad and
between said arcuate pocket surface and said arcuate shoe and
inwardly of each ledge, said end member extending substantially the
width of said elastomer pad whereby to completely block extrusion
of said pad from the inside between said arcuate pocket surface and
shoe when a load is placed on said movable connection causing said
pad to be compressed while still allowing for relative movement
between said arcuate pocket surface and said shoe to provide a
cushioning effect.
8. The invention of claim 7 wherein said non-extrudable end member
is a bar butted against an end of said pad.
9. The invention of claim 7 wherein said non-extrudable end member
is a bar imbedded in the end of said pad.
10. The invention of claim 7 wherein the non-extrudable end member
is a clip secured to the end of said pad.
11. The invention of claim 7 wherein the ledges are formed on the
ends of said pocket arcuate surface whereby said opening between
said surfaces increases when a load is placed on said fifth
wheel.
12. The invention of claim 7 wherein one ledge is formed on an end
of said pocket arcuate surface and another ledge is formed on an
end of said shoe.
Description
FIELD OF INVENTION
The present invention relates to fifth wheels for over the road
tractors by which trailers are demountably connected to the
tractors, and more particularly to an improved resilient pad placed
between the fifth wheel structure and each mounting bracket on the
tractor frame.
BACKGROUND OF THE INVENTION
Fifth wheel devices include a plate which supports upon its upper
surface the forward plate bed of a trailer. The underside of the
fifth wheel rests on two mounting brackets which are secured to
each side of the tractor frame. Pockets are formed at each edge of
the fifth wheel underside to receive and rest upon arcuate upper
portions of the mounting brackets so as to spread the forward
weight of the trailer over a substantial interface area; and
horizontal pins extend through the brackets and fifth wheel edges
to prevent vertical separation. Normally the interface has been
cushioned by an elastomer pad at each interface between mounting
bracket and fifth wheel pocket. However, it has been found that
during use the loads placed upon the fifth wheel have caused the
elastomer pad to be compressed to the point that it extrudes from
between the brackets and fifth wheel pockets thereby resulting in
losing the pad and its cushioning effect, or a permanent reduction
in cross section and consequent introduction of play between the
brackets and fifth wheel. This has occurred despite the
introduction of ledges on the ends of the pocket interface intended
to reduce the area through which the pad may extrude.
SUMMARY OF THE INVENTION
Accordingly it is an object of the invention to provide any
improved elastomer pad that will not be reduced by extrusion from
the interface of load supporting surfaces.
It is another object of the present invention to provide an
improved non-extrudable elastomer pad for placement between a fifth
wheel pocket and mounting bracket.
It is a further object of the present invention to provide a fifth
wheel pocket and improved elastomer pad to fit within the pocket
that will resist extrusion of the pad when the fifth wheel is
loaded.
It is still another object of the present invention to provide a
fifth wheel pocket and shoe with undulated surfaces to better
retain an elastomer pad against extrusion of the pad when the fifth
wheel is loaded.
Basically the present invention is the provision of nonextrudable
portions at the ends of an elastomer pad to block extrusion of the
elastomer material from the interface of a fifth-wheel and its
mounting bracket.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages will become apparent upon reading
the following detailed description in conjunction with the drawings
wherein:
FIG. 1 is a side elevation view of a tractor and trailer showing a
fifth wheel and one mounting bracket;
FIG. 2 is a perspective view of a fifth wheel and one mounting
bracket;
FIG. 3 is an exploded view of a fifth wheel (partial) and mounting
bracket with a pad constructed according to the present
invention;
FIG. 4 is a detailed sectional side elevation of a fifth wheel
pocket with pad divided to show both prior art (right side) and one
embodiment of the present invention (left side);
FIG. 5 is a perspective view of an embodiment of an elastomer pad
of the present invention;
FIG. 6 is a partial perspective view of another embodiment of an
elastomer pad of the present invention;
FIG. 7 is a partial perspective view of a further embodiment of an
elastomer pad of the present invention;
FIG. 8 is a detailed sectional side elevation of a modified
embodiment of the present invention wherein the fifth wheel pocket
surface and corresponding shoe surface are undulated to better
retain any elastomer pad; and
FIG. 9 is a side elevation view of a further embodiment of the
invention wherein the shoe is modified.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1-3 a fifth wheel generally 10 is pivotally
supported on two mounting brackets generally 12 (only one being
visible in the drawings) which are fastened to the frame 14 of a
tractor generally 16 and the forward end of a trailer generally 18
rests upon the upper surface 20 of the fifth wheel 10. Each bracket
12 includes an arcuate bearing surface 26 which is received in a
pocket 30 formed at the underside of each opposite edge of the
fifth wheel 10. In operation the fifth wheel 10 is pivotable on the
bracket bearing surfaces 12 and is retained against vertical
displacement by pins 34 which extend through each bracket 12 and
the skirt 36 of the fifth wheel.
As may be seen in FIGS. 3 and 4 the pocket 30 is a hollow
receptacle having an arcuate upper surface 40 which generally
conforms to the shape and size of the bracket bearing surface 26
and additionally receives an elastomer pad generally 44 and a rigid
shoe 46 between pocket surface 40 and bracket bearing surface 26.
When the fifth wheel is loaded the pad 44 will be compressed and
the vertical distance separating pocket arcuate surface 40 and shoe
46 (and bracket surface 26) will be reduced. However, the shoe 46
and arcuate surface 40 are normally sufficiently curved that the
ends thereof tend to relatively slip without substantially reducing
the horizontal space therebetween.
Transverse ledges 48, 50 project inwardly from each end of the
pocket arcuate surface 40 toward the ends of the shoe 46 (and
toward the bearing surface 26) but the ledges 48, 50 may not extend
into contact therewith as binding of the parts would thereby occur
upon a load being applied to the fifth wheel 10. Thus a substantial
clearance must remain between the ledges 48, 50 and shoe 46 thereby
leaving openings through which the elastomer pads 44 have
heretofore extruded (as illustrated in the right hand portion of
FIG. 4). It will be apparent that the same function may be obtained
if the ledges are formed on the shoe 46.
The present invention prevents such extrusion by utilizing non
extrudable end members generally 54, 56 at opposite ends of the
elastomer pad 44. As may be seen in the left hand portion of FIG. 4
the non-extrudable end member 54 rests against ledge 48 on the
pocket surface 40 and effectively blocks the opening left between
ledge 48 and shoe 46. Each end member 54 is sufficiently thick to
only block the clearance between a ledge 48 or 50 and the shoe 46
and need not fill the horizontal space between the pocket surface
40 adjacent the ledges and the free ends of shoe 46. Indeed it is
preferred that the end members 54 leave some play at that space so
as to allow some cushioning effect adjacent the ledges. The fact
that end member 54 is non-extrudable does not lessen the cushioning
effect of the elastomer pad 44 because at the location of ledge 48,
50 the major relative motion between shoe 46 and pocket surface 40
is parallel-sliding without significant compression, and the end
member 54 merely slides across the end of the shoe 46.
The non-extrudable end members 54, 56 may take various forms such
as illustrated in FIGS. 5-7. As shown in FIGURE 5 (and in FIG. 4)
the end members may be in the form of short bars freely associated
with the ends of pad 44 or secured thereto by adhesive or the like.
In FIG. 6 an end member 54' is shown comprising a short bar
imbedded in the elastomer pad 44'; and in FIG. 7 the end member 54"
is in the form of a "U" clip compressed upon the end of an
elastomer pad 44" or otherwise engaged on a formed pad end. A
variety of materials may be useful for whatever form of
non-extrudable end member that may be chosen such as rigid plastic
wood and metal, the latter being preferred.
In a preferred embodiment of the invention shown in FIG. 8, the
pocket surface 40' and corresponding surface of shoe 46' are
modified to include undulations transverse to the curvature of shoe
46 which serve to hinder relative movement or slippage between the
pad 44 and pocket surface 40' and to provide an increased interface
for the elastomer as the pad is initially compressed yet blocked
from extrusion by end members 54 and 56. It is also possible to
corrugate only one of the aforementioned surfaces to obtain
advantages of the present invention.
It is also possible to relocate at least one of the ledges 48, 50
from the pocket 30 to the shoe 46. As shown in FIG. 9 a ledge 50"
is formed at the outside of one end of shoe 46". However, to
facilitate assembly of pad 44 and such modified shoe 46" into a
pocket 30, so as to permit a sliding movement between the shoe 46"
and pad 44, it may be advantageous to provide one ledge 48 at one
end of the pocket surface 40 and the opposite ledge 50" on only one
end of shoe 46".
The foregoing details have been provided to describe the best mode
of the invention and still further variations and modifications may
be made without departing from the spirit and scope of the
invention which is defined in the following claims.
* * * * *